Alright since you people may be interested in this, I tried uharc0.6b at various settings and also FA with -m5 and -mx and additionally 7zip:ultra for comparison. This was done on random
preprocessed 660mb .forge file(from its original 448mb, using ztool). This is of course only single small test and doesnt have enough data to prove, but it does reflect with my other tests and show qualities and flaws well enough IMO.
On uharc these additional options were used: -md32768 -mm+
Then I tested 3 its main methods each: mx, mz, m3.
Results:
original: 660mb
uharc -mz: 317.22mb
uharc -mx: 290.79mb
uharc -m3: 284.27mb
7z -ultra: 271.37mb
FA -mx: 271.46mb
FA
-m5: 272.59mb
FA -m5 was absolutely quickest by significant margin to any other test, while resulting in only slightly bigger archive -
specifically 0.4145% difference from FA -mx. Halo? Anyone?
Ehm, anyway, for uharc except -mz all others were very slow, binding them to 4x4(if possible) would help but my guess is they would only match FA -mx speed then. FA -mx was still quicker than uharc(except -mz) but its true that FA use 2 cores while uharc used only 1.
7zip was great no doubt
!but!, first it is slow as hell despite using all 4 cores and second, it used over 3gb+ memory for this single 660mb file(!!!). FA was
much more rational with memory usage on both -m5 and -mx(1gb at peak and even shrinked during compression). Uharc had best memory usage, in -mx mode it used only 50mb(!), this would put him as a good candidate to chain it with 4x4 and srep could then pipe directly to 4xuha:ppm for only ~200mb usage without waiting for itself to finish 1st cycle.
Anyway, between uharc -mx and FA -m5 was still 6.67% difference
in favor of FA -m5!
In conclusion, this small test once again confirmed my thoughts, i.e. dont bother with anything higher than FA -m5, especially with ztool/srep, its really good enough and you are likely wasting your time with anything higher. Bulat has it figured out for us and gave us best and most optimized compression tool ever made. FA -m5 rule.
EDIT: I just tried MCM compressor with -m9 option that I was PM'd, 271.08mb + taking ages = not worth it